mirror of
https://github.com/henrydcase/pqc.git
synced 2024-11-27 01:41:40 +00:00
326 lines
9.4 KiB
C
326 lines
9.4 KiB
C
/*
|
|
The MIT License
|
|
|
|
Copyright (c) 2017 Daan Sprenkels <hello@dsprenkels.com>
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
of this software and associated documentation files (the "Software"), to deal
|
|
in the Software without restriction, including without limitation the rights
|
|
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
copies of the Software, and to permit persons to whom the Software is
|
|
furnished to do so, subject to the following conditions:
|
|
|
|
The above copyright notice and this permission notice shall be included in
|
|
all copies or substantial portions of the Software.
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
THE SOFTWARE.
|
|
*/
|
|
|
|
// In the case that are compiling on linux, we need to define _GNU_SOURCE
|
|
// *before* randombytes.h is included. Otherwise SYS_getrandom will not be
|
|
// declared.
|
|
#if defined(__linux__)
|
|
#define _GNU_SOURCE
|
|
#endif /* defined(__linux__) */
|
|
|
|
#include "randombytes.h"
|
|
|
|
#if defined(_WIN32)
|
|
/* Windows */
|
|
// NOLINTNEXTLINE(llvm-include-order): Include order required by Windows
|
|
#include <windows.h>
|
|
#include <wincrypt.h> /* CryptAcquireContext, CryptGenRandom */
|
|
#endif /* defined(_WIN32) */
|
|
|
|
#if defined(__linux__)
|
|
/* Linux */
|
|
// We would need to include <linux/random.h>, but not every target has access
|
|
// to the linux headers. We only need RNDGETENTCNT, so we instead inline it.
|
|
// RNDGETENTCNT is originally defined in `include/uapi/linux/random.h` in the
|
|
// linux repo.
|
|
#define RNDGETENTCNT 0x80045200
|
|
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <poll.h>
|
|
#include <stdint.h>
|
|
#include <stdio.h>
|
|
#include <sys/ioctl.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/syscall.h>
|
|
#include <sys/types.h>
|
|
#include <unistd.h>
|
|
|
|
// We need SSIZE_MAX as the maximum read len from /dev/urandom
|
|
#if !defined(SSIZE_MAX)
|
|
#define SSIZE_MAX (SIZE_MAX / 2 - 1)
|
|
#endif /* defined(SSIZE_MAX) */
|
|
|
|
#endif /* defined(__linux__) */
|
|
|
|
#if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
|
|
/* Dragonfly, FreeBSD, NetBSD, OpenBSD (has arc4random) */
|
|
#include <sys/param.h>
|
|
#if defined(BSD)
|
|
#include <stdlib.h>
|
|
#endif
|
|
#endif
|
|
|
|
#if defined(__EMSCRIPTEN__)
|
|
#include <assert.h>
|
|
#include <emscripten.h>
|
|
#include <errno.h>
|
|
#include <stdbool.h>
|
|
#endif /* defined(__EMSCRIPTEN__) */
|
|
|
|
#if defined(_WIN32)
|
|
static int randombytes_win32_randombytes(void *buf, const size_t n) {
|
|
HCRYPTPROV ctx;
|
|
BOOL tmp;
|
|
|
|
tmp = CryptAcquireContext(&ctx, NULL, NULL, PROV_RSA_FULL,
|
|
CRYPT_VERIFYCONTEXT);
|
|
if (tmp == FALSE) {
|
|
return -1;
|
|
}
|
|
|
|
tmp = CryptGenRandom(ctx, (DWORD)n, (BYTE *)buf);
|
|
if (tmp == FALSE) {
|
|
return -1;
|
|
}
|
|
|
|
tmp = CryptReleaseContext(ctx, 0);
|
|
if (tmp == FALSE) {
|
|
return -1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
#endif /* defined(_WIN32) */
|
|
|
|
#if defined(__linux__) && defined(SYS_getrandom)
|
|
static int randombytes_linux_randombytes_getrandom(void *buf, size_t n) {
|
|
/* I have thought about using a separate PRF, seeded by getrandom, but
|
|
* it turns out that the performance of getrandom is good enough
|
|
* (250 MB/s on my laptop).
|
|
*/
|
|
size_t offset = 0, chunk;
|
|
long int ret;
|
|
while (n > 0) {
|
|
/* getrandom does not allow chunks larger than 33554431 */
|
|
chunk = n <= 33554431 ? n : 33554431;
|
|
do {
|
|
ret = syscall(SYS_getrandom, (char *)buf + offset, chunk, 0);
|
|
} while (ret == -1 && errno == EINTR);
|
|
if (ret < 0) {
|
|
return (int) ret;
|
|
}
|
|
offset += (size_t) ret;
|
|
n -= (size_t) ret;
|
|
}
|
|
assert(n == 0);
|
|
return 0;
|
|
}
|
|
#endif /* defined(__linux__) && defined(SYS_getrandom) */
|
|
|
|
#if defined(__linux__) && !defined(SYS_getrandom)
|
|
static int randombytes_linux_read_entropy_ioctl(int device, int *entropy) {
|
|
return ioctl(device, RNDGETENTCNT, entropy);
|
|
}
|
|
|
|
static int randombytes_linux_read_entropy_proc(FILE *stream, int *entropy) {
|
|
int retcode;
|
|
do {
|
|
rewind(stream);
|
|
retcode = fscanf(stream, "%d", entropy);
|
|
} while (retcode != 1 && errno == EINTR);
|
|
if (retcode != 1) {
|
|
return -1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int randombytes_linux_wait_for_entropy(int device) {
|
|
/* We will block on /dev/random, because any increase in the OS' entropy
|
|
* level will unblock the request. I use poll here (as does libsodium),
|
|
* because we don't *actually* want to read from the device. */
|
|
enum { IOCTL,
|
|
PROC
|
|
} strategy = IOCTL;
|
|
const int bits = 128;
|
|
struct pollfd pfd;
|
|
int fd;
|
|
FILE *proc_file;
|
|
int retcode,
|
|
retcode_error = 0; // Used as return codes throughout this function
|
|
int entropy = 0;
|
|
|
|
/* If the device has enough entropy already, we will want to return early */
|
|
retcode = randombytes_linux_read_entropy_ioctl(device, &entropy);
|
|
if (retcode != 0 && errno == ENOTTY) {
|
|
/* The ioctl call on /dev/urandom has failed due to a ENOTTY (i.e.
|
|
* unsupported action). We will fall back to reading from
|
|
* `/proc/sys/kernel/random/entropy_avail`. This is obviously less
|
|
* ideal, but at this point it seems we have no better option. */
|
|
strategy = PROC;
|
|
// Open the entropy count file
|
|
proc_file = fopen("/proc/sys/kernel/random/entropy_avail", "r");
|
|
} else if (retcode != 0) {
|
|
// Unrecoverable ioctl error
|
|
return -1;
|
|
}
|
|
if (entropy >= bits) {
|
|
return 0;
|
|
}
|
|
|
|
do {
|
|
fd = open("/dev/random", O_RDONLY);
|
|
} while (fd == -1 && errno == EINTR); /* EAGAIN will not occur */
|
|
if (fd == -1) {
|
|
/* Unrecoverable IO error */
|
|
return -1;
|
|
}
|
|
|
|
pfd.fd = fd;
|
|
pfd.events = POLLIN;
|
|
for (;;) {
|
|
retcode = poll(&pfd, 1, -1);
|
|
if (retcode == -1 && (errno == EINTR || errno == EAGAIN)) {
|
|
continue;
|
|
} else if (retcode == 1) {
|
|
if (strategy == IOCTL) {
|
|
retcode =
|
|
randombytes_linux_read_entropy_ioctl(device, &entropy);
|
|
} else if (strategy == PROC) {
|
|
retcode =
|
|
randombytes_linux_read_entropy_proc(proc_file, &entropy);
|
|
} else {
|
|
return -1; // Unreachable
|
|
}
|
|
|
|
if (retcode != 0) {
|
|
// Unrecoverable I/O error
|
|
retcode_error = retcode;
|
|
break;
|
|
}
|
|
if (entropy >= bits) {
|
|
break;
|
|
}
|
|
} else {
|
|
// Unreachable: poll() should only return -1 or 1
|
|
retcode_error = -1;
|
|
break;
|
|
}
|
|
}
|
|
do {
|
|
retcode = close(fd);
|
|
} while (retcode == -1 && errno == EINTR);
|
|
if (strategy == PROC) {
|
|
do {
|
|
retcode = fclose(proc_file);
|
|
} while (retcode == -1 && errno == EINTR);
|
|
}
|
|
if (retcode_error != 0) {
|
|
return retcode_error;
|
|
}
|
|
return retcode;
|
|
}
|
|
|
|
static int randombytes_linux_randombytes_urandom(void *buf, size_t n) {
|
|
int fd;
|
|
size_t offset = 0, count;
|
|
ssize_t tmp;
|
|
do {
|
|
fd = open("/dev/urandom", O_RDONLY);
|
|
} while (fd == -1 && errno == EINTR);
|
|
if (fd == -1) {
|
|
return -1;
|
|
}
|
|
if (randombytes_linux_wait_for_entropy(fd) == -1) {
|
|
return -1;
|
|
}
|
|
|
|
while (n > 0) {
|
|
count = n <= SSIZE_MAX ? n : SSIZE_MAX;
|
|
tmp = read(fd, (char *)buf + offset, count);
|
|
if (tmp == -1 && (errno == EAGAIN || errno == EINTR)) {
|
|
continue;
|
|
}
|
|
if (tmp == -1) {
|
|
return -1; /* Unrecoverable IO error */
|
|
}
|
|
offset += tmp;
|
|
n -= tmp;
|
|
}
|
|
assert(n == 0);
|
|
return 0;
|
|
}
|
|
#endif /* defined(__linux__) && !defined(SYS_getrandom) */
|
|
|
|
#if defined(BSD)
|
|
static int randombytes_bsd_randombytes(void *buf, size_t n) {
|
|
arc4random_buf(buf, n);
|
|
return 0;
|
|
}
|
|
#endif /* defined(BSD) */
|
|
|
|
#if defined(__EMSCRIPTEN__)
|
|
static int randombytes_js_randombytes_nodejs(void *buf, size_t n) {
|
|
const int ret = EM_ASM_INT({
|
|
var crypto;
|
|
try {
|
|
crypto = require('crypto');
|
|
} catch (error) {
|
|
return -2;
|
|
}
|
|
try {
|
|
writeArrayToMemory(crypto.randomBytes($1), $0);
|
|
return 0;
|
|
} catch (error) {
|
|
return -1;
|
|
}
|
|
},
|
|
buf, n);
|
|
switch (ret) {
|
|
case 0:
|
|
return 0;
|
|
case -1:
|
|
errno = EINVAL;
|
|
return -1;
|
|
case -2:
|
|
errno = ENOSYS;
|
|
return -1;
|
|
}
|
|
assert(false); // Unreachable
|
|
}
|
|
#endif /* defined(__EMSCRIPTEN__) */
|
|
|
|
int randombytes(uint8_t *buf, size_t n) {
|
|
#if defined(__EMSCRIPTEN__)
|
|
return randombytes_js_randombytes_nodejs(buf, n);
|
|
#elif defined(__linux__)
|
|
#if defined(SYS_getrandom)
|
|
/* Use getrandom system call */
|
|
return randombytes_linux_randombytes_getrandom(buf, n);
|
|
#else
|
|
/* When we have enough entropy, we can read from /dev/urandom */
|
|
return randombytes_linux_randombytes_urandom(buf, n);
|
|
#endif
|
|
#elif defined(BSD)
|
|
/* Use arc4random system call */
|
|
return randombytes_bsd_randombytes(buf, n);
|
|
#elif defined(_WIN32)
|
|
/* Use windows API */
|
|
return randombytes_win32_randombytes(buf, n);
|
|
#else
|
|
#error "randombytes(...) is not supported on this platform"
|
|
#endif
|
|
}
|